It's Only Natural: Using Polymers in Drug Delivery

A book explains the many pharmaceutical applications of polymers from natural sources.
Jan 02, 2009

Natural-Based Polymers for Biomedical Applications is a comprehensive, well-researched, and clearly written book that achieves an optimal balance between depth and breadth of information. The authors are biomaterial and biomedical experts from various academic research institutions from all over the world, including the United States, Europe, and Asia. Pharmaceutical scientists working in the fields of biopolymeric drug delivery, sustained-release formulation, natural-based polymeric nanoparticles, hydrogels, polysaccharides, biopolymers, and biomaterials will find this book useful.

Natural-Based Polymers for Biomedical Applications, R.L. Reis, Ed., CRC Press, Boca Raton, FL, 2008, 802 pp., ISBN: 9781420076073
The book's six main parts describe natural-based polymers, biomimetic coatings, biodegradable scaffolds for tissue regeneration, naturally-derived hydrogels, sustainedrelease systems, and the biocompatibility of natural-based polymers. Of particular interest to formulation scientists are Parts I and V, which present information about polysaccharide carriers, liposomes, polysaccharide hydrogels, and polysaccharide sustained-release systems.

Part I discusses the purification, processing, degradation kinetics, and drug delivery of various classes of natural-based polymers in detail. The authors provide in-depth information about various polysaccharides used in drug formulations, as excipients and as carriers, and about smart systems.

Part II describes how biomaterials' surfaces are affected by cellular material. The authors discuss practical applications such as ensuring biocompatibility, surface modification for enhanced properties, and nanotechnology techniques to provide surface functionality. This section would interest biomedical scientists more than drug-delivery and formulation scientists.

The following section describes methods for creating scaffolds with designed characteristics for tissue-engineering applications. With the exception of a subsection about drug delivery using elastin-like polymers, this section is not particularly relevant to manufacturers of final dosage forms.

Hydrogels are the subject of Part IV. The authors describe how scientists can harness the unique fundamental physicochemical properties of natural polymers to use hydrogels as matrices for drug delivery and regenerative medicine. This section examines polysaccharide-based hydrogels, alginate hydrogels, and fibrin matrices. Chapter 18 describes some properties of individual types of polysaccharide hydrogel materials, a subject of interest to drug-delivery formulation scientists.

Part V continues the examination of drug-delivery applications. The section includes information about designing advanced systems for the controlled delivery of small molecules and macromolecules. Among other topics, the authors consider thiolated chitosans in noninvasive drug delivery and chitosan–polysaccharide blended nanoparticles for controlled drug delivery.

Unfortunately, this part of the book gives certain subjects short shrift and omits others completely. For example, the pharmaceutical particle-processing technique of supercritical fluid using CO2 is presented briefly. The drug-delivery topics of liposomes and pegylation are likewise touched upon, but not explained in depth.

In addition, this section does not encompass all aspects of sustained drug delivery, but rather restricts itself to polysaccharide particles for drug delivery. The physicochemical properties and their relationships to particle drug-release behavior also are not presented in depth, nor are analytical and physical characterization techniques.

Part VI focuses on autoimmune responses at a cellular level in the context of tissue engineering and biocompatibility. The information presented on the biocompatibility of these pharmaceutical polysaccharide polymers may be helpful to producers of final dosage forms.

The authors and editors manage to present these important topics without overwhelming the reader. The presentation is clear, and many helpful tables, fine images, schematics, and diagrams are included throughout the book to aid the reader. For example, certain figures show the chemical structures of various polysaccharides, and Table 1.1 lists macromolecular prodrugs of chemotherapeutics conjugated to polysaccharide carriers. Particularly interesting to drug delivery scientists, Tables 23.1 and 23.2 list several types of drugs and macromolecules encapsulated in biodegradeable polymers as microparticles and nanoparticles, respectively.

Natural-Based Polymers for Biomedical Applications is recommended to pharmaceutical scientists in industry and academia working with polysaccharide polymers as excipients and carriers. The book would also be a valuable resource for educators, postdoctoral scholars, and graduate students working with natural-based polymers in the design and development of dosage forms and controlled-release delivery systems.

Heidi M. Mansour, PhD, RPh, is an assistant professor of pharmaceutical sciences and pharmaceutical technology at the University of Kentucky College of Pharmacy, 725 Rose St., 411A Pharmacy Bldg., Lexington, KY 40536-0082, tel. 859.257.1571,